Yes, Ho went Commie to secure Soviet support, since US decided to back France. US should just have dictated freedom for Asian colonies occupied by Japan in the peace deals after WW2. The Europeans would be angry, but it would have been better in the long run.
Much as I want to support the idea of the US supporting Ho in 1945, the above bit about Ho being a latecomer to the Communist fold is just not true.
He was in France when WWI ended, and controversy raged through Socialist circles about whether or not to adopt Leninism as their new guide; the socialists who did so became the founders of the Third International aka "Communists."
Ho Chi Minh was one of those charter member Communists--literally; his signature appears on the founding document of the French Communist Party.
It is quite true that the decisive factor for him was the various factions' stand on colonialism; he was impressed with the Bolshevik's forthright anti-colonialism versus the weaseling, ambivalence, or downright imperialism of the mainstream socialists. But he was a Communist as early as anyone else outside of Russia and he stayed one to his dying day.
This works against the idea that Truman might have nevertheless supported him but doesn't entirely rule it out; in the depths of the McCarthy era the US did play off Tito in Yugoslavia against Stalin after all.
I'm quite sure that had Ho been able to get at least moral support from the USA, and had that "moral support" gone so far as to refrain from helping France in its re-colonization efforts in Indochina, then he would have handily secured control of Vietnam itself, probably Laos as well, and France would have had no foothold. IIRC France had zero logistical capacity to return to Vietnam in the years after WWII and OTL the regime sent its forces there in American ships. That regime by the way was not Gaullist--DeGaulle would not become French President until the 1960s and the collapse of the 4th Republic--nope, these colonialists were under a Socialist government, one that included the French Communist Party in its coalition--and that party, perhaps on its own hook, perhaps under orders from Stalin, I forget, was also committed to France regaining all its colonies.
Under those circumstances, I expect that relations between Ho and Stalin would be rather cool; turning to frosty if Vietnam and the USA got close. In that case I guess the Vietnamese regime would have been far less radical--still quite left-wing by American standards, perhaps going so far as the Arbenz government in Guatemala or the Mossadeqh ministry in Iran as to nationalize land and key industries, but probably not daring to have the sort of land reform that did happen in the North OTL. Of course the Latin American and Middle Eastern reformers became the bugbears of the early Eisenhower (and late Truman for that matter) years and were overthrown in US-directed coups; if Ho were not, it would be the difference between "sons-of-bitches" and "our son-of-a-bitch."
Say what you will against the Viet Minh, I can't believe they were in any way worse than people like the Somozas of Nicaragua (of whom the infamous "our-son-of-a-bitch" phrase was said, attributed to various American leaders) or the Duvaliers of Haiti. Or just about any tinpot dictator in the Western sphere of influence. And I'd argue, they were clearly better in their commitment to the betterment of the lives of ordinary citizens.
The dark side of American alliance would be that they might have to slack off on that very commitment. But I'd think Ho, provided he gave his pro-American credentials in the form of critical independence of both Stalin and Mao in the world diplomatic sphere, would have been too valuable an ally to lose and would instead be the showcase of how American policy really really wasn't reactionary at all, and it was Stalin who was the enemy of left-wing progressivism.